Project Summary American Indian (Native) youth have the highest incidence and prevalence of pediatric type 2 diabetes of all racial/ethnic groups in the United States. Lifestyle modification has been shown to prevent type 2 diabetes among high-risk adults by up to 58%, including among Native populations, but similar efforts in Native youth have been largely unsuccessful. We recently developed a behavioral intervention for Native youth-parent dyads called Tribal Turning Point (TTP). In a randomized pilot study, we demonstrated feasibility of program delivery, acceptability by Native stakeholders, and significant treatment effects for multiple obesity measures. We now propose to conduct a randomized controlled trial to rigorously evaluate the effect of TTP on diabetes risk factors in 300 overweight/obese Native youth aged 7-10 years who are living in urban or rural communities served by the Indian Health Services. Within each community, youth will be randomized to the TTP program or a general health and safety control program. The multi-component TTP intervention is a youth-centered adaptation of the Diabetes Prevention Program designed to reduce diabetes risk factors by improving activity and dietary behaviors. The 12-month intervention includes 12 active learning group classes, 7 individual youth/parent motivational interviewing counseling sessions, and community-specific resource toolboxes. In this trial, we will assess the effect of TTP on anthropometric, metabolic, and behavioral risk factors for type 2 diabetes at the end of the intervention (12mo) and after 1 year of follow-up (24mo). With an eye toward widespread dissemination of the program, we will also collect qualitative data on factors related to participant engagement, program delivery, and potential for sustainability throughout the award period, which will guide future implementation efforts. The specific aims of our proposal are: 1) Evaluate the effect of TTP on anthropometric (primary: BMI; secondary: BMI z-score, waist circumference) and metabolic (primary: fasting insulin; secondary: hemoglobin A1c) diabetes risk factors at 12 and 24 months. 2) Examine the effect of TTP on health behaviors (diet, physical activity) and the extent to which improvements in health behaviors mediate the effects of TTP on diabetes risk factors. 3) Explore individual, organizational, and community-level factors related to participant engagement, program implementation, and potential for sustained delivery.